Ensaios de fermentação para produção de Bacillus thuringiensis Berliner 1911, a partir da farinha de macaxeira (Manihot utilissima Pohl) e toxicidade à Aedes aegypti Linnaeus 1769 e à Anopheles spp. (Diptera: Culicidae)

Abstract

The utilization of Bacillus thuringiensis based bioinsecticides on disease vector control programs provides countless advantages. This Gram-positive bacterium, aerobic, rod-shaped bacterium, during sporulation produces inclusions crystalline cytoplasmic called as Cry proteins, that shows high specificity larvicide activity against different insect orders. However shows to be safe for a man as well minimize the impacts on the environment. The first studies focus the production of this bacterium. Were used low-cost products as components for submerged fermentation. In this process there is no addition of new culture way during the bacterial growth, allowing alterations on the environment’s physic-chemical conditions, favoring the production of this microorganism, by stimulating its sporulation when the medium becomes inhospitable. The present work used submerged fermentation as a tool for the production of a strain of Bacillus thuringiensis, from the UFAM collection, called BtAm 27. In bacterial growth was used as carbon source, Cassava (Manihot utilissima Pohl) flour hydrolyzed with α-amilase (Thermamyl®) and glucoamilase (Novozymes®), and also yeast extract, KH2PO, MgSO4.7H2O, MnSO4.4H2O, CaCl2.2H2O, (NH4)2SO4. From this culture medium a yeast with a yield of 4.8 g/L of bacterium dry mass was obtained and the isolate was found to keep its larvicidal activity against Aedes aegypti and Anopheles spp.